Cloves are the unripe flower buds (10 - 17 mm long) of the up to 14 m tall clove tree (Syzygium aromaticum) of the Myrtaceae family. The tree is indigenous to the Moluccas in South-East Asia.

Cloves are harvested just before they open, then destalked before being sun-dried. In the course of the drying process, they change color from carmine to light to dark brown.

The clove consists of the head formed of the four petals, which enclose the style and stamens, and the four-sided calyx, which forms a unit with the calyx tube.

The term spice is used to refer to plant parts which serve to improve the odor and flavor of foods. They contain essential oils and other ingredients which have a strong seasoning action.

Spices are processed, cleaned, graded and carefully packaged for overseas dispatch in the countries where they are cultivated. They are dried to preserve them for transport and storage. In consumer countries, they are delivered to spice mills, where they are cleaned and graded again, ready for sale in unground or ground form.

Spices are classified by the plant parts used:

Fruit and seed spices (e.g. pepper, cardamom, nutmeg)

Bud and flower spices (e.g. cloves)

Bark spices (e.g. cinnamon)

Root spices (ginger, turmeric)

Leaf spices (bay leaf)

Cloves are a very valuable, expensive product.

Oil content:

15.0 - 20.0% essential oils [1], in particular eugenol

7.0 - 10.0% fatty oils

Quality / Duration of storage

High-quality cloves should be oil-rich, whole, unbroken and stalkless and must not contain any woody, brittle cloves. They should be reddish-brown to brown in color and the head should be light brown and closed.

A float test may be used to determine clove quality:

good, sound cloves sink, or float with their heads vertically upwards

lower grade cloves float horizontally on the surface of the water

In general, cloves from the East Indies are of better quality than those produced in East Africa, which holds a greater share of the world market, however.

Provided that the recommended storage conditions are complied with, cloves may be kept for approx. 24 months.

Intended use

Cloves are used in cooking (desserts, bakery products, meat, fish, red cabbage, mulled wine) and in the food, pharmaceutical and cosmetics industries. They are also used to produce oil of cloves, the main constituent of which is eugenol. Eugenol is used, among other things, to perfume soaps and as a dental anesthetic and an additive in dental filling material [10].

Figures

(Click on the individual Figures to enlarge them.)

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Countries of origin

This Table shows only a selection of the most important countries of origin and should not be thought of as exhaustive.

Ventilated containers are used, subject to compliance with lower limits for water content of goods, packaging and flooring. Alternatively, open-sided containers, with floor dunnage or pallets, may be used to ensure adequate ventilation. The containers should be stowed below deck in areas where adequate ventilation is ensured and the side tarpaulins should be rolled up [11].

Cargo handling

In damp weather (rain, snow), the cargo must be protected from moisture, since this may lead to mold, spoilage and self-heating.

Hooks must not be used in handling bagged goods as they subject the bags to point loads, so damaging them. Due to their shape, plate or bag hooks apply an area load and are thus more suitable for handling bags.

In order to ensure safe transport, the cargo must be stowed and secured in the means of transport in such a manner that it cannot slip or shift during transport. If loss of volume and degradation of quality are to be avoided, the packages must not be damaged by other articles or items of cargo.

Cloves should be transported in areas which exhibit the lowest temperatures during the voyage and are dry. In any event, storage beneath the weather deck or, in the case of shipping in containers, in the uppermost layer on deck, must be avoided as the deck or container is strongly heated by the intense tropical sun and, at temperatures of > 25°C, essential oils may be lost and there is a risk of self-heating.

Spices are hygroscopic goods (hygroscopicity), which interact with the moisture in the air. The risk of mold growth is naturally at its greatest in warm, damp air. The cargo may become musty, and the risk of self-heating increases with an elevated air moisture content.

Cloves should be stowed away from goods which are sensitive to moisture/humidity or release moisture (e.g. copra).

In order to prevent condensation on the ship's side or container walls from affecting the cargo, care should be taken to leave a clear gap between the cargo stack and the ship's side or container wall. Cloves must be protected from all forms of moisture (seawater, rain, condensation water).

Once damp, cloves are absolutely worthless, as there is no way of reconditioning them. They become sticky, soft and gray and can no longer be ground. For this reason, it is absolutely essential to avoid rel. humidities of > 75%.

If the product is at "shipping dryness", it does not have to be ventilated during transport. However, if the water content does not meet these guidelines, the following ventilation measures should be implemented to eliminate the potential for dampness:

In order to avoid formation of mold, the stowage space should be cool, dry and, most particularly, easy to ventilate. Constant, very good ventilation is necessary, to dissipate the water vapor released by the cargo and to cool the cargo in the case of incipient self-heating.

In addition to the residual water content remaining after drying, the risk of self-heating is also explained by the relatively high content of fatty oils.

Oil content:

15.0 - 20.0% essential oils [1], in particular eugenol

7.0 - 10.0% fatty oils

If the relative humidity of the ambient air is too high (> 75%), there is a risk of the cloves becoming wet and developing a tendency to self-heating. This risk is further increased by excessively high storage temperatures.

Cloves have a strong, pleasant but pungent odor. Therefore, do not stow together with coffee, tea and other odor-sensitive goods.

When transporting spices, it is important to retain the content of essential oils to the greatest possible extent, since these substances, together with other constituents, such as fatty oils, tannins and bitter principles, determine the odor and flavor and thus quality of the spices.

The essential oils are readily volatilized and the seasoning action of the spices is consequently reduced. Volatilization of the essential oils is primarily determined by temperature. The higher is the ambient temperature, the more the essential oils are volatilized, as may be recognized by the intense odor in the hold.

Passive behavior

Cloves are highly odor-sensitive and should therefore not be stowed together with odor-emitting products.

Cloves are very fragile and should be protected from excessive pressure. Broken flower heads allow the essential oils contained in the cloves to volatilize more readily and thus cause an increase in odor intensity.

With bagged cargo, point loads applied for example by hooks may result in damage (tears) to the bags and thus in loss of volume. Plate or bag hooks, which, due to their shape, distribute the load and reduce the risk of damage, should thus be used.